Xcaddy not found using caddy:2.1.0-builder

1. The problem I’m having:

I am trying to build a custom container image using caddy:2.1.0-builder and getting “/bin/sh: xcaddy: not found”. My Dockerfile:

FROM caddy:2.1.0-builder AS builder

RUN xcaddy build \
    --with github.com/mholt/caddy-ratelimit@v0.1.0

FROM caddy:2.1.0

COPY --from=builder /usr/bin/caddy /usr/bin/caddy

I haven’t used Docker all that much so it is quite possible I am doing something stupid.

2. Error messages and/or full log output:

/bin/sh: xcaddy: not found

docker build -t caddy:latest .

[+] Building 2.4s (7/8)                                                                                                                                               docker:orbstack
 => [internal] load build definition from Dockerfile                                                                                                                             0.0s
 => => transferring dockerfile: 252B                                                                                                                                             0.0s
 => [internal] load metadata for docker.io/library/caddy:2.1.0                                                                                                                   2.1s
 => [internal] load metadata for docker.io/library/caddy:2.1.0-builder                                                                                                           0.0s
 => [internal] load .dockerignore                                                                                                                                                0.0s
 => => transferring context: 2B                                                                                                                                                  0.0s
 => CACHED [builder 1/2] FROM docker.io/library/caddy:2.1.0-builder                                                                                                              0.0s
 => CACHED [stage-1 1/2] FROM docker.io/library/caddy:2.1.0@sha256:9ee709b080aacb1a5cae6c4cb654d950f1ded75d7a2277a792860bb28134158e                                              0.0s
 => ERROR [builder 2/2] RUN xcaddy build     --with github.com/mholt/caddy-ratelimit@v0.1.0                                                                                      0.2s
------                                                                                                                                                                                
 > [builder 2/2] RUN xcaddy build     --with github.com/mholt/caddy-ratelimit@v0.1.0:
0.150 /bin/sh: xcaddy: not found
------
Dockerfile:3
--------------------
   2 |     
   3 | >>> RUN xcaddy build \
   4 | >>>     --with github.com/mholt/caddy-ratelimit@v0.1.0
   5 |     
--------------------
ERROR: failed to solve: process "/bin/sh -c xcaddy build     --with github.com/mholt/caddy-ratelimit@v0.1.0" did not complete successfully: exit code: 127

3. Caddy version:

docker.io/library/caddy:2.1.0-builder 

4. How I installed and ran Caddy:

a. System environment:

Mac OS 15.4. Apple M3 Max.
Docker version 28.0.4, build b8034c0

5. Links to relevant resources:

https://hub.docker.com/_/caddy

Thanks

It should be .10, not .1

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